The field of the present invention is devices for augmenting intake to an internal combustion engine.
A myriad of devices have been developed for augmenting intake volume, conditioning intake flow, improving mixture and the like. Once such device previously employed uses the variable pressure within the crankcase, resulting from movement of the piston, to increase and condition intake flow. Such secondary intake devices employ a secondary passage with one end open to the intake port and the other end associated with a diaphragm located within the crankcase. During the exhaust cycle, reduced pressure within the crankcase causes the diaphragm to suck air/fuel mixture into the secondary passage. During the intake cycle, the mixture is ejected into the intake passage to improve inlet efficiency.
A specific difficulty found to be associated with the foregoing device is that the overpressure within the crankcase is also developed during the power stroke. During the power stroke, the intake valving is closed and ejection of additional air/fuel mixture creates back flow and other flow currents within the intake system which may, under certain conditions, reduce rather than increase inlet efficiency.